System of electrical distribution.



No. 706,609. Patented Aug. 12, I902.

C. P. STEINMETZ.

SYSTEM OF ELECTRICAL DISTRIBUTION.

(Application filed Jan. 2, 1901.)

("0 Model.)

Witnesses. Invenfior. am QLM Charles PSGeinmetz,

UNITED STATES PATENT OFFICE.

CHARLES P. STEINMETZ, OF SOIIENEOTADY, NEW YORK, ASSIGNOR TO GENERALELECTRIC COMPANY, A CORPORATION OF NE\V YORK.

SYSTEM OF ELECTRICAL DISTRIBUTION.

SEEGIFICATION forming part of Letters Patent No. 706,609, dated August12, 1902.

Application filed January 2, 1901. Serial No. 41,807. (No model.)

To all whom it may concern.-

Be it known that LCHARLES P. STEINMETZ,

a citizen of the United States, residing at.

Schenectady, county of Schenectady, State of New York, have inventedcertain new and useful Improvements in Systems of ElectricalDistribution, (Case No. 1,670,) of which the following is aspecification.

The invention hereinafter described and claimed provides an automaticmeans for maintaining a constant or practically constant consumption ofpower in consumptioncircuits, the aggregate resistance of which isvariable.

Various applications of the invention may be made in practiceas, forexample, in connection with electric furnaces, in which it is desirablethat the energy consumed should be uniform throughout normal operation.Since the resistance of the electric furnace varies with thetemperature, it has heretofore been found necessary to vary the voltageimpressed upon the furnace by some system of hand regulation. My presentinvention enables this result to be accomplished automatically.

In the drawings, Figure 1 is a diagram explanatory in a general way ofthe nature of the invention, and Fig. 2 is a diagram representing theinvention as applied to an electric furnace.

In carrying out the invention I make use of reactances of oppositesign-as, for example, an inductance-coil and a condenserconnected inseries across supply-mains which receive power from some suitablesource. In Fig. 1 the inductance-coil and the condenser are indicated,respectively, at 1 and 2, power being supplied to the terminals throughmains 3 and 4, connected through suitable distributing-conductors 5 and6 with a source of alternating current, (indicated conventionally at'7.) The inductance-coil and the condenser are so proportioned thattheir respective reactances at normal frequency of the generating source7 are equal and opposite, thisproportioningofpartscorrespondingtoresonance relati0n,as will readily beunderstood by those skilled in the art. Across one of these reactancedevicesas,for example, the condenser 2-I shunt a constant resistance 8,having a value in ohms equal to the reactanco of the condenser expressedin ohms. Across the remaining reactanceto wit, the inductancecoil 1Ishunt another resistance 9, which may vary between any desired limits.With the construction thus described the power eX- pended in theconstant resistance 8 added to the power expended in the variableresistance 9 is a constant quantity. When the power consumed in one ofthe circuits or resistances decreases, that in the other increases, thesum of the powers expended in both circuits or resistances, however,remaining constant.

Fig. 2 shows the invention as applied to an electric furnace, thesupply-mains 3 4 and the reactances 1 and 2 corresponding to the sameparts, as indicated in Fig. 1. The electric furnace is indicatedconventionally at 10 and may be of any desired construction. It is,however, here shown as provided with two separate consumption-circuits.One of the circuits, which corresponds to the terminals 11 12, receivescurrent through conductors 13 14-, connected across the condenser2, andconveys this current through the substance 15 to be heated, in whichsubstance the ends of the terminals are inserted to suitable depth. Theother set of terminals 16 and 17 are joined by a rod of conductingmaterial 18, preferably of carbon, this rod being buried in the mass ofthe material 15 to be acted upon by the furnace. This latter set ofterminals receives current through operative connections across theinductance-coil 1, the connections in this instance being effected bymeans of a transformer 19, the purpose of which is to transmit currentto the terminals 16 and 17 and at the same time maintain the circuit ofthese terminals electrically distinct from the circuit of the terminals11 and 12. The currents of these respective sets of terminals thereforedo not interfere in their passage through the material 15, upon whichthe currents act. When the furnace is cold, the resistance of thematerial to be heated is comparatively high, and it is for this reasonthat I provide the carbon rod 18, which I use for the purpose ofinitially heating the material 15. When this operation is to beperformed, the switch 20 is left open, the entire power beingconcentrated in the rod 18, which thereupon heats the surroundingmaterial. As the term perature of the latter rises its conductivityincreases. After the initial heating has proceeded a sufficient lengthof time, thereby causing the conductivity of the material 15 toincrease, the switch 20 may then be closed and current then is suppliedjointly to the two sets of terminals 11 12 and 16 17. It should beobserved that the resistance of the circuit between the terminals 16 and17 is sufficiently near constancy as to satisfy the condition ofconstant resistance, the relations of which with respect to thereactance about which it is shunted were sufficiently set forth inconnection with the description of Fig. 1.

It is to be observed that in Fig. 1 the constant resistance is shown asshunted about the condenser and the variable resistance about theinductance. These connections may, however, be reversed withoutaffecting the operation of the invention and are so illustrated in Fig.2, in which the variable resistance represented by the circuit betweenthe terminals 11 and 12 is shunted about the condenser and the constantresistance between the terminals 16 and 17 is operatively connected inshunt to the inductance-coil 1.

Wherever herein I speak of reactances of opposite sign, I mean toincludedevices which possess capacity and inductance,respec tively. For thepurpose of illustration I have shown a condenser as typifying a devicepossessing capacity and an inductance-coil as typifying a devicepossessing inductance; but it will be evident to those skilled in theart that other devices possessing these same qualities may beemployed-such, for example, as polariza- Lion-cells, transformers withopen magnetic circuits, tranformers with condensers in theirsecondaries, (Q-

What I claim as new, and desire to secure by Letters Patent of theUnited States, is-

l. The combination of constant-potential supply-mains, energy-consumingmeans supplied therefrom, and means for causing the consumption of powerin said energy-consuming means to remain constant regardless ofvariation of the aggregate resistance of said energy-consuming means.

2. The combination of supply-mains, consumption-circuits fed therefrom,and means for automatically maintaining a constant consumption of powerin said circuits regardless of variation of the aggregate resistance ofsaid circuits.

3. The combination of constant-potential mains, reactances of oppositesign in series across said mains,a non-inductive energy-consuming deviceoperativcly connected across one of said reactances, and anotherenergyconsuming device operatively connected across another of saidreactances.

4. The combination of constant-potential mains, reactances of oppositesign in series across said mains, and non-inductive resistances in shuntrespectively across said reactances.

5. The combination of constant-potential mains, reactances of oppositesign in series across said mains, a circuit in shunt to one of saidreactances and containing an approximately constant resistance, and acircuit in shunt to another of said reactances and containing a variableresistance.

6. The combination of constant-potential mains, reactances of oppositesign in series across said mains, a resistance arranged to receivecurrent transmitted through a circuit in shunt to one of said reactancesof the same value in ohms as the resistance, and another resistancereceiving energy from a circuit in shunt to another of said reactances.

7. The combination of constant-potential mains, reactances of oppositesign in series across said mains, a resistance arranged to receivecurrent transmitted through a circuit in shunt to one of said reactancesof the same value in ohms as the resistance, and a variable resistancereceiving energy from a circuit in shunt to another of said reactances.

In witness whereof I have hereunto set my hand this 29th day ofDecember, 1900.

CHARLES I. STEINME'JZ.

Witnesses:

BENJAMIN B. IIULL, Mano/mm E. Woonnnv.

